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Increase in Newly Diagnosed HIV Infections Among Young Black Men Who Have Sex with Men --- Milwaukee County, Wisconsin, 1999--2008

During 2001--2006, new human immunodeficiency virus (HIV) diagnoses among black men aged 13--24 years who have sex with men (MSM) in 33 states increased by 93% (1). The Wisconsin Division of Public Health (WDPH) recently reported to CDC a 144% increase during 2000--2008 in HIV diagnoses among black MSM aged 15--29 years in Milwaukee County. In October 2009, the City of Milwaukee Health Department (MHD), WDPH, and CDC investigated whether the increase in HIV infections among young black MSM in Milwaukee represented increased HIV transmission or simply better identification of prevalent infections. This report describes the results of that investigation, which indicated that a new "social networks" HIV testing strategy and the recent expansion of better targeted HIV testing efforts accounted for few diagnoses among young black MSM and occurred after HIV diagnoses increased, respectively. Therefore, although some diagnoses were made because of intensified testing, an increase in HIV transmission likely occurred. Moreover, an increase in syphilis diagnoses among young black MSM in Milwaukee preceded the increase in HIV diagnoses, which suggests that changes in risk behavior or sexual networks might explain the increase. These findings highlight the need for new or improved interventions promoting prevention education, early HIV detection, and entry to care for young HIV-infected and at-risk black MSM in Milwaukee.

CDC, MHD, and WDPH reviewed the timing of recently implemented HIV testing strategies and examined data from two sources: 1) name-based, confidential HIV surveillance data (collected in Wisconsin since 1985) and 2) HIV testing data from publicly funded test sites. HIV diagnoses that were not reported previously were considered new diagnoses. Trends were analyzed comparing the number of new HIV diagnoses (counted by year in which the diagnosis was made), number of tests performed in publicly funded test sites, and the proportion of those tests that were positive among black and nonblack (white and Hispanic) MSM, stratified by age group (15--19, 20--24, 25--29, and ≥30 years). Because of small numbers, year-to-year differences were highly variable, so CDC compared aggregate data for the years 1999--2001 (before diagnoses increased and before new testing strategies were adopted) and 2006--2008 (after diagnoses increased and after new testing strategies were adopted). WDPH determined whether the new social networks testing strategy or traditional testing strategies were associated with cases identified.

The trends in HIV diagnoses also were compared with trends in diagnoses of primary or secondary syphilis in young black MSM in Milwaukee because HIV and syphilis are both transmitted through unprotected sex. Primary and secondary syphilis occur within a few months of infection, so increases in primary and secondary syphilis suggest increases in HIV incidence also might have occurred. CDC compared primary and secondary syphilis incidence for 1999--2001 and 2006--2008 using WDPH surveillance data. Because syphilis surveillance data in Milwaukee do not document HIV coinfection, CDC also reviewed MHD partner services records, in which coinfection is recorded routinely, for all primary and secondary syphilis cases among black MSM aged 15--29 years diagnosed during January 2006--June 2009. The latter period was chosen to maximize the number of cases considered (the period for trend analyses ended in 2008 because of concerns about delayed reporting of more recent diagnoses to surveillance).

During 2006--2008, WDPH intensified HIV testing statewide. Beginning in 2006, a new social networks testing strategy encouraged MSM who were diagnosed recently with HIV to recruit MSM within their social networks for HIV testing. In 2007, WDPH intensified targeted HIV testing to black MSM by urging publicly funded test sites trained in the social networks testing strategy to administer ≥45% of all tests to black and Hispanic MSM. The extent to which these strategies detected infections among previously undiagnosed black MSM was unclear.

Comparing 1999--2001 and 2006--2008, new HIV diagnoses increased among black MSM aged 15--19, 20--24, and 25--29 years (by 143%, 245%, and 78%, respectively) (Table). In contrast, new diagnoses increased less among nonblack MSM aged 20--24 years (by 14%) and 25--29 years (by 45%),* and they decreased among black and nonblack MSM aged ≥30 years (by 40% and 1%, respectively). Comparing 1999--2001 and 2006--2008, the percentage increase in the number of HIV tests among young black MSM aged 15--19, 20--24, and 25--29 years ranged from 90% to 372%, whereas the percentage increase in the number of HIV tests among nonblack MSM in each of these age groups ranged from 44% to 63%. Along with the increased number of tests conducted, increased HIV positivity among black MSM aged 15--19 and 20--24 years and nonblack MSM aged 25--29 years also contributed to the trend of increasing diagnoses in these groups.

During 2006--2008, the new social networks testing strategy resulted in new HIV diagnoses only among black MSM. However, within the 15--19, 20--24, and 25--29 year age groups, this strategy accounted for only 11.8%, 5.3%, and 6.3% of new diagnoses, respectively. Moreover, the effort to expand and better target testing in publicly funded test sites began after increases in HIV diagnoses and positivity were observed among black MSM aged 15--29 years (Figure). Although data were unavailable to describe testing trends in privately funded test sites during this period, the proportion of new diagnoses in these test sites decreased from 56% to 24% among black MSM and from 22% to 4% among nonblack MSM from 1999--2001 to 2006--2008; the number of diagnoses among black MSM aged 15--29 years in privately funded sites increased from 15 to 17 during these periods.†

An increase in syphilis diagnoses was noted first in 2005, 1 year before the increase in HIV diagnoses was first noted (Figure). Comparing 1999--2001 to 2006--2008, the number of syphilis diagnoses increased from one to 19 among black MSM and from zero to four among nonblack MSM aged 15--29 years. Investigators reviewed records of the 22 black MSM aged 15--29 years with primary or secondary syphilis diagnosed and reported to MHD during January 2006--June 2009. Of the 22 men, five had only syphilis diagnosed, nine had concurrent diagnoses of HIV and syphilis, six contracted syphilis after HIV diagnosis, and two contracted HIV after syphilis diagnosis.

Editorial Note

Increases in both HIV and syphilis diagnoses were confirmed among young black MSM in Milwaukee County during 1999--2008. More complete ascertainment of prevalent infection among young black MSM likely was aided by the expansion and improved targeting of HIV testing that occurred in Milwaukee County during the period of observation. However, expanded and better targeted testing began after HIV diagnoses and positivity began to increase and, therefore, could not have accounted for the observed increase. Further, if increased testing primarily identified MSM who had been HIV-infected but undiagnosed for a number of years, an increase in diagnoses mainly in older MSM would have been expected. Instead, diagnoses were observed to have decreased among black MSM aged ≥30 years, and both diagnoses and positivity increased among black MSM aged 15--19 years. Moreover, the proportion of all black MSM HIV diagnoses accounted for by MSM aged 15--19 years increased from 8% to 16% from 1999--2001 to 2006--2008, but nonblack MSM aged 15--19 years accounted for <5% of nonblack MSM HIV diagnoses during both periods. Assuming that sexual exposure to HIV has had less time to occur in the 15--19 year age group than in any other age group, diagnoses in this group are more likely to represent recent infection.

Other evidence also suggests that increased HIV diagnoses at least partly resulted from increased transmission. The social networks testing strategy, one of the most efficient and effective means for identifying undiagnosed MSM (2), identified very few new cases. Antecedent increases in primary and secondary syphilis diagnoses also suggest changes in risk behaviors or sexual networks among young black MSM that could have facilitated the spread of HIV (3). An increase in HIV transmission among young black MSM in Milwaukee County is consistent with a report of increased HIV incidence among MSM nationwide (4).

The findings in this report are subject to at least three limitations. First, HIV testing data were not available to assess HIV testing trends in privately funded test sites. An increase in HIV testing by private providers might have increased diagnoses, given CDC's 2006 recommendation of at least annual HIV testing for persons at high risk for HIV (5). However, the number of diagnoses from privately funded test sites during 2006--2008 was relatively small, and the proportion of diagnoses occurring in privately funded test sites declined from 1999--2001 to 2006--2008. Therefore, increased testing in privately funded sites is unlikely to have accounted for the observed increase in diagnoses among young black MSM. Second, increased syphilis screening might have contributed to the increase in syphilis cases. However, screening likely did not account for all of the increase because primary and secondary syphilis are symptomatic, prompting presentation for care and subsequent diagnosis. Finally, the lack of HIV incidence data limits conclusions regarding the timing of infection among young MSM.

The results of this investigation suggest that increased HIV diagnoses during 1999--2008 might be attributable to increased HIV transmission during the period among young MSM in Milwaukee County and that young black MSM remain the group most affected by HIV. In 2008, black MSM aged 15--29 years accounted for 71% of new diagnoses among black MSM in Milwaukee County. Nationwide, in 2006, black MSM aged 13--29 years accounted for an estimated 52% of new HIV infections among black MSM, and they accounted for nearly as many infections as Hispanic and white MSM in this age group combined (6). The concentration of infections among these young men underscores the need for interventions to address their risk for HIV infection. As a result of this investigation, MHD has developed, funded, and is implementing a peer-focused and community-based action plan to promote prevention education, early HIV detection, and entry into care among young black MSM. If evaluation shows these interventions to be effective, other jurisdictions should consider implementing similar measures.

* Because no diagnoses occurred during 1999--2001 among nonblack MSM aged 15--19 years, change in diagnoses or positivity could not be calculated.

† Trends in the proportions of tests conducted in privately funded test sites were assessed by taking the difference between the total number of diagnoses and the number diagnosed in publicly funded test sites. For this analysis, this difference was used as a proxy for number of tests in privately funded sites.

What is already known on this topic?

Human immunodeficiency virus (HIV) diagnoses among young black men who have sex with men (MSM) have increased recently in the United States; possible explanations include expanded HIV testing or increased HIV transmission.

What is added by this report?

Expanded HIV testing did not account for increased HIV diagnoses that occurred among young black MSM in Milwaukee County, Wisconsin, from 1999--2001 to 2006--2008; increased transmission likely occurred.

What are the implications for public health practice?

New or improved interventions to reduce HIV risk and increase HIV testing and care for those found to be infected among young black MSM are needed.

TABLE. Trends in HIV diagnoses, testing, and HIV test positivity among black and nonblack men who have sex with men, by age group --- Milwaukee County, Wisconsin, 1999--2008*†

Age group (yrs)

No. of HIV diagnoses

No. of tests performed in publicly funded test sites

HIV positivity in publicly funded test sites (%)§

1999--2001

2006--2008

% change

1999--2001

2006--2008

% change

1999--2001

2006--2008

% change

15--19

Black

7

17

143

42

180

329

4.8

9.4

98.3

Nonblack

0

<5

---

127

199

57

0.0

<2.5

---

20--24

Black

11

38

245

82

387

372

2.4

5.9

143.7

Nonblack

7

8

14

460

663

44

1.5

1.2

-20.7

25--29

Black

9

16

78

91

173

90

8.8

8.1

-7.9

Nonblack

11

16

45

481

786

63

1.5

2.0

39.9

≥30 yrs

Black

60

36

-40

259

423

63

6.2

6.9

11.0

Nonblack

72

71

-1

1,912

2,464

29

2.2

1.4

-35.3

Total

177

---

---

3,454

5,275

53

2.4

2.7

12.2

Sources: Wisconsin Enhanced HIV/AIDS Reporting System (number of diagnoses) and Wisconsin Division of Public Health (number of tests and positivity).

* Percentage change reflects the difference between the two 3-year periods.

† The nonblack subgroup consisted of Hispanic and white men.

§ HIV test positivity is calculated as the percentage of positive tests of all tests completed in publicly funded test sites. Positivity from other sites could not be calculated because data were not available.

FIGURE. Number of new diagnoses of HIV and primary and secondary syphilis and HIV test positivity among black men aged 15--29 years who have sex with men --- Milwaukee County, Wisconsin, 1999--2008*†

† HIV test positivity is calculated as the percentage of positive tests of all tests completed in publicly funded test sites. Positivity from other sites could not be calculated because data were not available.

§ In 2007, the Wisconsin Division of Public Health urged publicly funded test sites to intensify targeted testing of black men who have sex with men.

Alternate Text: The figure above shows the number of new diagnoses of HIV and primary and secondary syphilis and HIV test positivity among black men aged 15-29 years who have sex with men in Milwaukee County, Wisconsin, during 1999-2008. From 1999-2001 to 2006-2008, a new "social networks" testing strategy resulted in new HIV diagnoses only among black MSM. However, within the 15-19, 20-24, and 25-29 year age groups, this strategy accounted for only 11.8%, 5.3%, and 6.3% of new diagnoses, respectively. Moreover, the effort to expand and better target testing in publicly funded test sites began after increases in HIV diagnoses and positivity were observed among black MSM aged 15-29 years.

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